The apple rootstock CX5 is valued for its cold tolerance and dwarfing characteristics, positioning it as a promising candidate for overcoming cold stress and modernizing cultivation systems in China's apple industry. However, its broader adoption is hindered by challenges such as poor rooting ability, which limit the efficiency of conventional breeding approaches. Biotechnological breeding can offer a solution to this bottleneck, and establishing a genetic transformation system for CX5 is a pivotal step. Based on previous findings that MdAIL5 significantly enhances adventitious root regeneration, we introduced the PRI101-MdAIL5-GFP vector into CX5 using the Agrobacterium rhizogenes strain K599-mediated system and systematically optimized key transformation parameters. Results showed that using leaves from shoots subcultured for 40 d, infected with bacterial solution at an OD600 of 0.6−0.8 for 5 min, achieved a maximum hairy root induction rate of 28.89%. Furthermore, on medium supplemented with 1.0 mg·L−1 TDZ and 0.1 mg·L−1 IAA, the regeneration rate of adventitious buds from transgenic hairy roots reached 3.33%. Overexpression of MdAIL5 enhanced the rooting ability of CX5 tissue culture plantlets. In summary, we successfully established a genetic transformation system for CX5 and demonstrated that overexpression of MdAIL5 significantly enhances rooting ability. This system provides a crucial technical foundation for genetically improving the poor rooting phenotype and other target traits of this cold-tolerant dwarf rootstock.
In this study, we provide a comprehensive assessment of the genetic diversity and population structure of cornelian cherry (Cornus mas) using six simple sequence repeat (SSR) loci across nine Hungarian localities. All loci amplified successfully, producing 79 alleles with an average of 13.17 alleles per locus, indicating high polymorphism. Except for one locus, all others showed polymorphic information content (PIC) values > 0.70, demonstrating their high informativeness for a genetic analysis of the population. The observed and expected heterozygosity ranged from 0.359 to 0.891 and from 0.381 to 0.884, respectively, suggesting substantial genetic variation and approximate Hardy–Weinberg equilibrium. Multivariate analyses showed a moderate population structure: principal coordinate analysis and a discriminant analysis of principal components consistently distinguished the Markóc population as a distinct genetic cluster, while showing the other populations to have a partial overlap, indicating gene flow. The unweighted pair-group method with an arithmetic mean and Nei's FST values of 0.004–0.237, respectively, confirmed the strong isolation of the Markóc population, moderate differentiation of the Telki population, and low differentiation among North-Transdanubian populations. Analysis using the software STRUCTURE v2.3.4 supported four genetic clusters (K = 4), including one highly distinct population and three admixed groups. These findings highlight a significant genetic diversity within Hungarian C. mas populations and emphasize the importance of conserving both isolated and interconnected populations to maintain genetic resources for future breeding programs.
Salt stress is a major abiotic stress that impairs plant growth and development, affecting gene transcription, metabolite profiles, and overall phenotypes. However, the underlying molecular response mechanisms, especially those mediated by hydrogen-rich water (HRW), remain unclear. In this study, we integrated physiological, transcriptomic, and metabolomic analyses to explore the effects of HRW on salt stress tolerance in Prunus davidiana seeds. The results showed that, compared with salt stress alone, exogenous hydrogen-rich water (HRW) treatment significantly reduced oxidative damage in peach seeds. Specifically, HRW decreased the accumulation of superoxide anion (O2−) and the content of malondialdehyde (MDA), while increasing the activities of superoxide dismutase (SOD) and peroxidase (POD). Integrated transcriptomic and metabolomic analyses revealed significant reprogramming of genes and metabolites, particularly those involved in the phenylpropanoid and flavonoid biosynthesis pathways. Salt stress markedly suppressed the biosynthesis and accumulation of secondary metabolites such as flavonoids, alkaloids, and chlorogenic acid by downregulating key rate-limiting genes (PAL, C4H, HCT). Exogenous HRW treatment effectively reversed the repression of these genes and restored related metabolite levels to nearly those of the control group. In summary, hydrogen-rich water acts as an alleviator of salt stress, and the identified metabolites and key rate-limiting genes offer potential targets for improving salt tolerance in mountain peach seeds.
The NAC transcription factor family represents a unique class of plant-specific regulators involved in abiotic stress responses. In this study, a MiNAC2D gene was obtained from the mango genome and transcriptome. Subcellular localization confirmed the nuclear localization of MiNAC2D. Expression analysis revealed that its transcript levels were highest in leaves and were significantly upregulated under drought, low temperature, and salt stresses. To investigate its biological function, MiNAC2D was overexpressed in Arabidopsis, tomato, and mango. Transgenic Arabidopsis and tomato plants showed enhanced performance under abiotic stress conditions, including higher seed germination rates, increased root length, and improved survival rates. In addition, transgenic plants displayed significantly reduced leaf damage compared to wild-type (WT) controls. Transcriptome profiling of WT and transgenic mango roots under drought stress identified 145 differentially expressed genes involved in signaling pathways, 14 of which were validated by RT-qPCR. Under salt stress, 92 differentially expressed signaling pathway-related genes were identified, with ten confirmed by RT-qPCR. These results suggest that MiNAC2D may enhance drought tolerance through the abscisic acid (ABA) pathway and improve salt tolerance via mechanisms involving ion homeostasis and the ethylene pathway. Overall, this study demonstrates the role of MiNAC2D in enhancing abiotic stress tolerance and provides a foundation for further exploration of its regulatory network in mango.
Differences in the fruit peel color of jaboticaba (Myrciaria cauliflora) are primarily determined by the content and composition of anthocyanins. In this study, a combined strategy of targeted metabolomics and transcriptomics was employed to systematically elucidate the molecular regulatory mechanisms underlying fruit peel coloration in the 'White', 'Evergreen', and 'Sabara' cultivars. The results indicated that cyanidin and delphinidin were the major anthocyanin components dominating peel coloration, with cyanidin making the most significant contribution. Notably, the 'Sabara' cultivar exhibited an extremely high anthocyanin content, resulting in a deep black peel color. Weighted Gene Co-expression Network Analysis (WGCNA) and Mfuzz clustering identified nine key structural genes (PAL_2, 4CL_4, C4H, CHS, CHI_1, CHI_2, F3H, F3'H, and ANS) involved in the entire biosynthetic pathway, whose expression profiles were highly consistent with anthocyanin accumulation. Simultaneously, 7 McMYB and 12 McbHLH transcription factors were found to be co-expressed with these structural genes, displaying contrasting expression patterns between 'White' and 'Sabara'. Furthermore, potential binding sites for McMYB4, McMYB24, McMYB73, and McbHLH130 were discovered in the promoter regions of these structural genes. Dual-luciferase reporter assays further demonstrated that McMYB4 significantly suppressed the promoter activities of McPAL_2 and McC4H, which was consistent with the co-expression network analysis. This study reveals the molecular regulatory mechanisms governing the differences in fruit peel color among 'White', 'Evergreen', and 'Sabara' at the mature stage, providing a theoretical basis for the genetic improvement of color traits in jaboticaba.
Xizang, located in the southwestern region of the Qinghai–Xizang Plateau and often referred to as 'the roof of the world', is the highest-altitude grape-cultivation region globally. Although its viticultural heritage dates back to the Tubo Dynasty (7th century CE), industry development was impeded for over a millennium owing to bioclimatic extremes and technological limitations in the pre-industrial era. However, with major advances in transportation infrastructure and agrotechnological innovation, the viticulture industry began to experience transformative growth in the 21st century. As a result, the Southern Xizang Valley (Yarlung Zangbo Valley) and Eastern Xizang High-Mountain Canyon Area (Hengduan Mountains Region) have emerged as the dominant grape-growing areas in Xizang. In parallel, global climate change is reshaping the Xizang environment, enhancing the viability of high-altitude viticulture and enabling unprecedented expansion of climatically suitable viticultural zones. Despite these developments, systematic reviews of viticulture-related literature for this region remain scarce. Therefore, we conducted this systematic literature review to comprehensively characterize the viticulture industry in Xizang, incorporating its geomorphological and climatic context and multiple aspects of grape cultivation, including historical development, current practices, and fruit quality attributes. We also examined the impacts of global warming on regional viticulture and berry composition, elucidated key challenges in both industry practices and scientific research, and proposed evidence-based strategies for future industry advancement. This review provides a scientific reference for rational planning, cultivation model selection, and in-depth research on Xizang grapes.
'Faustrime' is a hybrid between Australian finger lime, also known as caviar lime (Citrus australasica), and 'Eustis' limequat (C. aurantiifolia × Fortunella japonica), originally developed in California. Despite its growing commercial interest, this genotype has not yet been comprehensively characterised from morphological and agronomic perspectives. In the present study, we assessed flowering intensity, fruit set, parthenocarpic ability, and fruit development. Notably, 'Faustrime' requires a lower thermal accumulation to induce flowering through CiFT3 gene expression than sweet orange (Citrus sinensis [L.] Osbeck), and it displays a marked capacity for summer flowering. Regarding fruit set, the hybrid achieves an optimal crop load due to its high parthenocarpic ability, which exceeds that of both sweet orange and its parental species, C. australasica. Consistent with this behaviour, 'Faustrime' synthesises higher levels of auxin and bioactive gibberellins (GA1, GA4, and GA7) than its progenitors. In addition, this hybrid exhibits high nutritional value and distinctive organoleptic characteristics. Its pollen grains are pentacolpate, and both the ovary and fruit are oval in shape. The fruit contains small, spherical juice vesicles with a slightly acidic taste and a crunchy texture, which are highly appreciated in haute cuisine. Furthermore, the flavedo shows a high concentration of essential oils, mainly D-limonene (52%), γ-terpinene (12%), citronellal (15%), and δ-3-carene (5%), together with n-alkanes and coumarins, compounds valued in the pharmaceutical, perfumery, and cosmetic industries. Overall, these characteristics underline the potential of 'Faustrime' as a novel citrus genotype with agronomically relevant traits and prospective economic viability.
In response to the severe impact of common diseases such as measles, wilt disease, and rotten holes on grape yield and quality in grape cultivation, as well as the limitations of existing detection models in identifying subtle lesions and locating irregular lesions, this study aims to propose an improved YOLOv11n-based detection model for grape leaf diseases. The goal is to enhance the accuracy and robustness of grape leaf disease detection, thereby providing technical support for the early diagnosis, prevention, and control of grape diseases. An improved model was constructed based on the YOLOv11n algorithm, with key improvements including: embedding the DPPA dual-channel attention module in the backbone network to fuse multi-scale features through dual pathways of local detail perception and global context capture, thereby enhancing the discriminative ability for heterogeneous lesions; replacing the original C3K2 structure with the C2f-DCN module, which introduces deformable convolution to adaptively capture the morphology of irregular lesions and improve localization accuracy. A grape leaf disease dataset (GLDDD) containing 5,000 images was used, divided into training, validation, and test sets in an 8:1:1 ratio. Combined with data augmentation techniques such as Mosaic-9 and Randaugment, the model was trained with 250 training iterations. The improvement effects were verified through ablation experiments and comparative experiments. The following were observed: (1) The performance of the improved model was significantly enhanced, with an mAP of 95.7%, showing excellent performance among similar models. (2) Ablation experiments indicated that the C2f-DCN module had a prominent effect in improving precision and mAP, with minimal impact on parameter count and model size; the DPPA module could improve precision to a certain extent, and their combination effectively optimized model performance. However, although the DFF module improved recall, it significantly increased the parameter count and model size while leading to a decrease in precision. (3) Comparative experiments showed that the improved DCD-YOLO model achieved a 4.9% higher detection precision for measles disease than YOLOv11n and a 5.4% higher precision than YOLOv11n-DPPA. The average detection accuracy for the three diseases was significantly higher than that of other comparative models. (4) The model achieved the optimal performance balance at 250 training epochs, with a precision of 92.3%, a recall of 90.1%, and an mAP of 95.7%, demonstrating the best performance in detection accuracy and coverage capability. The improved YOLOv11n model proposed in this study effectively addresses the issues of difficulty in identifying subtle grape leaf lesions and low localization accuracy of irregular lesions by introducing the DPPA and C2f-DCN modules. It significantly enhances the performance of grape leaf disease detection, meets the practical needs of grape disease detection, and provides a feasible technical solution for the automated detection of crop diseases in the agricultural field.
Starch degradation is a critical process influencing fruit quality and shelf life during postharvest ripening of banana. Sucrose nonfermenting-1-related protein kinase 2 (SnRK2) is a plant-specific Ser/Thr protein kinase family primarily involved in abscisic acid (ABA) signaling; however, its role in regulating fruit starch degradation remains largely unclear. In this study, 14 MaSnRK2 genes were identified from the Musa acuminata genome and classified into three phylogenetic groups, all containing a conserved S_TKc catalytic domain. Evolutionary analysis indicated that the MaSnRK2 family has undergone strong purifying selection, with six tandem duplication events contributing to its expansion. Promoter analysis revealed abundant cis-acting elements associated with development, hormone signaling, and stress responses. Among the identified members, MaSnRK2.10 exhibited distinct functional differentiation and was markedly upregulated during fruit ripening, suggesting a specialized role in starch metabolism. Subcellular localization analysis showed that the MaSnRK2.10 protein is predominantly localized to the nucleus and cell membrane. Functional assays demonstrated that transient silencing of MaSnRK2.10 increased total starch content, whereas transient overexpression reduced starch accumulation in banana fruit, confirming its involvement in the regulation of starch degradation. Furthermore, coexpression analysis and molecular docking predict that ERF, NAC1, NAC2, and NAC3 may bind to the MaSnRK2.10 promoter, suggesting a complex transcriptional regulatory network. Collectively, this study systematically characterizes the genome-wide features of the MaSnRK2 family and identifies MaSnRK2.10 as a key regulator of starch degradation, providing valuable molecular insights and targets for improving banana fruit quality and shelf life.
Understanding relationships among pear (Pyrus spp.) accessions and ensuring their correct identification is critical for breeding and germplasm management. In this study, we analyzed 445 accessions, primarily Pyrus communis, using three genotyping approaches to assess population structure, determine parentage, and identify cultivars. ddRAD libraries were prepared using the restriction enzymes AvaII and MspI. From more than 7,000 SNPs pruned for linkage disequilibrium, we distinguished species, identified clones, commonly used breeding cultivars and their offspring, and detected misclassified accessions. From the identified SNPs, we developed a panel of over 100 amplicon-based SNP (abSNP) markers. In parallel, we designed a novel set of 17 SSR markers, allowing both marker types to be genotyped in a single PCR reaction and directly compared. The SSR panel proved highly robust, achieving a probability of identity (PID) of 9.1 & times; 10-25, which allowed for discrimination among individual accessions and facilitated parentage assignment. In contrast, abSNP markers were less reliable for parentage analysis due to amplification bias associated with the highly heterogeneous pear genome. Nevertheless, abSNP markers were highly effective for clone identification, cultivar discrimination, and population-level studies. These results provide a frameworkfor cost-effective genotyping and germplasm management in pear breeding programs.
Widely cultivated for ornamental and fruit tree purposes in East Asia, Prunus mume Sieb. et Zucc. is best known for its early flowering in late winter to early spring. The timing of flowering is an interesting parameter that affects fruit yield, fruit quality, and ornamental value, but it is strongly influenced by environmental changes. This review brings together recent progress in understanding how flowering time in Prunus mume is controlled by environmental signals, plant hormones, and gene regulation. Bud dormancy, which ensures survival through winter, moves through several stages before flowering, and is primarily regulated by chilling accumulation and subsequent heat requirements, while photoperiod plays a secondary modulatory role. Hormones such as gibberellins (GA) and abscisic acid (ABA) play opposite roles in controlling bud break and dormancy, while cytokinins (CK), auxin (IAA), and ethylene coordinate floral development. At the molecular level, flowering regulation involves several critical genes, including DORMANCY-ASSOCIATED MADS-box (DAM) and SHORT VEGETATIVE PHASE (SVP) genes that maintain dormancy, and FLOWERING LOCUS T (FT), SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1), LEAFY (LFY), and APETALA1 (AP1) genes that promote flowering transition. Recent studies have also identified NAC (NAM, ATAF1/2, and CUC2) transcription factors that fine-tune early flowering in Prunus mume. Advances in genomics, transcriptomics, and phenological models have improved knowledge of flowering time control, although more work is needed to connect molecular mechanisms with field adaptation. This understanding is important for breeding cultivars suited to future climates.
Root systems are critical to orchard productivity and resilience, yet their size and structure remain poorly characterized in modern high-density apple (Malus & times; domestica) plantings. We examined root architectural traits of G.935 and M.9Nic29 apple rootstocks over two years in a high-density orchard, grafted either to 'Honeycrisp' or self-grafted. Each rootstock displayed distinct root architectural and growth patterns. G.935 had significantly (p < 0.05) higher total root surface area, total root volume, and number of fine roots than M.9Nic29 over all time points. G.935 grafted to 'Honeycrisp' produced significantly (p < 0.05) smaller root systems than self-grafted trees, whereas M.9Nic29 showed no such difference. The root growth of M.9Nic29 generally did not differ based on scion, but Honeycrisp/G.935 reduced in size over the winter, whereas G.935/G.935 root systems stayed the same size. Our results also indicate the potential for root-root interactions in high-density orchards. All tree types had root growth of at least 45.72 cm (1.5 ft) in each direction during the study period. These findings provide insights into the root systems of apple trees in a high-density orchard and demonstrate that scion-rootstock interactions can primarily drive root system growth under intense planting systems.
Modern apple cultivars tend to have significantly lower phenolic content than wild species and heritage cultivars. Although the phytochemical makeup of apple fruit affects important traits, such as nutrition, flavour, texture and disease resistance, phytochemical-based breeding strategies for apple improvement are lacking. We studied the relationships between fruit phenolic content and sensory traits in a seedling population derived from crosses between the domesticated and wild apple species. We also investigated the potential of genomic selection for breeding new high-health cultivars faster. Phenolic content, sensory traits, sugar levels, and a stable vitamin C glycoside (ascorbic acid 2-beta-glucoside [AA-2 beta G]) were assessed to estimate the genetic parameters of these traits. Phenolic compounds (chalcones, flavanols [FLAVA], cinnamic acids), triterpenoids (TRITP), carbohydrates (CARBO), AA-2 beta G, and sensory traits (astringency [ASTR], sourness [SOUR]) were found to be moderately heritable (h(2) = 0.35-0.50), while fructose-glucose ratio (FGRAT), fruit size (SIZE), and overall eating quality (EQUAL) were highly heritable (h2 > 0.75). FGRAT was strongly correlated (> 0.70) with sweetness (SWEET) and EQUAL. Phenolics and AA-2 beta G were positively correlated, but both displayed moderate negative correlations with EQUAL. TRITP content displayed a moderate positive correlation with EQUAL and negative correlation with SOUR and ASTR. The accuracy of genomic prediction ranged from 0.50 (FLAVA) to 0.90 (SIZE) and was highly correlated with trait heritability. The knowledge derived from this study can assist in designing DNA-based fast-breeding strategies for simultaneous improvement of phytochemicals and sensory traits.
The historical Washington State University Sweet Cherry Breeding Program, led by Dr. Thomas Toyama from 1963 to 1985, developed important and distinct vars and 30 remaining selections contribute significantly to commercial production worldwide and current breeding. However, the origins of this valuable 'Toyama germplasm' are unclear. This study relied on hand-written breeding records of crosses and verified pedigree information to analyze the output of this historical breeding program and characterize the genetic origins of Toyama's germplasm. Dr. Toyama used 103 unique parents from diverse origins to create 241 families, and at least 5,182 germinated seeds formed from at least 88,000 pollinated flowers. Most parents were from North America, especially the most-used 'Stella' that generated half of all germinated seeds. Half of the Toyama germplasm's ancestry was traced to pre-1900 European cultivars, with 'Napoleon' representing 25%-33% of the genetic background. For extant selected germplasm, 'Stella' and two of Toyama's own selections were the most used parents, accounting for 52% of recorded parentages. Similar ancestry contributions for selected and pre-selected germplasm indicate that the diverse germplasm accessed persists in extant breeding parents and commercial cultivars. Exploitation of self-fertility and Toyama's signature complementing of 'Stella' with early-season French cultivars could explain the high success rates of pollinated flowers converted into germinated seeds and eventually into cultivars. DNA-based diagnostics could further reveal the ancestry and valuable alleles of this germplasm to inform future breeding endeavors.
Stone cell formation, resulting from aberrant lignin deposition in parenchyma cells, is a key determinant of pear fruit quality. Although exogenous calcium application is known to inhibit lignin biosynthesis and stone cell development, the underlying molecular mechanism involving calcium sensor proteins remains poorly understood. This study aimed to elucidate the molecular pathway by which calcium signaling modulates lignin biosynthesis. Our findings demonstrate that the calmodulin-like protein PbCML46 significantly suppresses lignin accumulation. This function was validated through complementary approaches, including transient injection in pear fruit and stable overexpression in pear calli. A yeast two-hybrid screen revealed that PbCML46 specifically interacts with the bHLH transcription factor PbbHLH96, an interaction further confirmed by pull-down and luciferase complementation imaging (LCI) assays. Further yeast one-hybrid (Y1H), electrophoretic mobility shift assay (EMSA), and luciferase (LUC) reporter assays analysis showed that PbbHLH96 directly binds to the MYC cis-element in the PbCAD6 promoter and functions as a transcriptional repressor. Dual-luciferase reporter (DLR) and in vivo co-expression assays indicated that PbCML46 markedly enhances the repressive activity of PbbHLH96 on the PbCAD6 promoter, an effect strictly dependent on PbbHLH96. In conclusion, this study reveals a Ca2+-initiated regulatory cascade in which calcium signaling promotes the interaction between the sensor PbCML46 and the transcriptional repressor PbbHLH96, leading to cooperative suppression of the key lignin biosynthetic gene PbCAD6 and thereby negatively regulating lignin deposition in pear stone cells. These findings provide novel mechanistic insights into how calcium signaling improves fruit quality.
Fruit texture is a critical quality trait affecting the consumer acceptance and processing suitability of jujube (Ziziphus jujuba Mill.). Soluble sugars and organic acids are not only fundamental to flavor but also serve as key metabolic indicators associated with textural diversity. However, how the accumulation soluble sugars and organic acids relates to textural variation remains largely unexplored. This study systematically evaluated 109 jujube germplasm accessions for soluble sugars, titratable acidity, and fruit hardness at full-red maturity. Hierarchical clustering based on these traits classified the germplasm into three distinct groups: Group I (high acidity and low hardness, 29.36%), Group II (balanced traits, 55.96%), and Group III (high sugar and high hardness, 14.68%). Textural profile analysis revealed that Group III exhibited significantly superior texture, with hardness, gumminess, and chewiness exceeding those of Group I by 97.99%, 99.91%, and 210.22%, respectively. High-performance liquid chromatography (HPLC)-based quantification of the primary metabolites showed that the favourable texture of Group III was associated with a markedly higher accumulation of sucrose, fructose, and glucose. In contrast, Group possessed significantly high concentrations of citric acid and malic acid, which were higher than those of Group III by 401.75% and 141.27%, respectively, and which correlated with its softer texture. Correlation and principal component analyses further highlighted a strong antagonistic relationship between sugar and organic acid accumulation, with sugars positively and organic acids negatively associated with key textural parameters. This germplasm-based classification, coupled with the identified sugar-organic acid signatures, provides a clear phenotypic and biochemical frameworkfor breeding, and suggests that sugar and organic acid metabolism may indirectly influence fruit texture through osmotic regulation and modulation of the cell wall microenvironment.
The GDSL-type esterase/lipase family plays a crucial role in regulating plant growth and development, modulating responses to abiotic stresses, activating pathogen defense mechanisms, and governing lipid metabolism pathways. In this study, a comprehensive genome-wide analysis using integrated BLASTP and HMMSEARCH strategies identified 38 MdGELP genes in apple, which were mapped to 14 chromosomes. Phylogenetic analysis classified these genes into three major clades (A, B, and C). Multiple sequence alignment, combined with analyses of conserved domains and motifs, revealed a high degree of sequence conservation among MdGELP proteins. Promoter cis-acting element analysis uncovered diverse regulatory motifs, while gene duplication analysis indicated that segmental and tandem duplications were the primary evolutionary forces driving the expansion of the GELP family in apple. Collinearity analysis further highlighted significant homology between MdGELPs and AtGELPs. Quantitative expression assays revealed tissue-specific expression patterns, with MdGELPs showing preferential expression in leaves and flowers. Expression profiling under abiotic stresses (ABA, low-temperature, and salt) demonstrated their positive responsiveness to environmental challenges. This study not only establishes a theoretical foundation for exploring the biological functions of MdGELPs but also provides critical insights for future research in this field.
The limited postharvest life of grapes poses a significant challenge to their commercial value. This study employed an integrated approach, combining in vitro and in vivo antifungal assays, storage experiments at two temperatures (4 and 26 degrees C), and physiological and molecular analyses, to elucidate the effects and underlying mechanisms of chitosan (CTS), and salicylic acid (SA) on preserving the quality of 'Shine Muscat' grapes. The results demonstrated significant antifungal activity of both CTS and SA against Aspergillus niger, with 2% CTS inducing hyphal deformities, and 1.0 mmol/L SA strongly inhibiting conidiation. Under storage conditions, 2.0% CTS at 4 degrees C most effectively reduced decay, fruit drop, and weight loss, while enhancing antioxidant enzyme activities (SOD, CAT) and minimizing malondialdehyde accumulation. Conversely, at 26 degrees C, 1.0 mmol/L SA was superior in alleviating quality deterioration by activating the antioxidant system and delaying acid degradation. Quantitative analysis revealed that the optimal treatments (2.0% CTS and 1.0 mmol/L SA) upregulated downregulating senescence- and browning-related genes (VvPPO, VvPOD, VvLOX). Mechanistically, CTS primarily formed a protective semipermeable coating to reduce water loss and pathogen contact, whereas SA enhanced membrane stability and systemic antioxidant capacity. These findings elucidate the distinct mechanisms of CTS and SA and provide a theoretical basis for developing targeted, eco-efficient preservation strategies based on storage
Jujube (Ziziphus jujuba Mill.) fruit is an exceptional source of ascorbic acid (AsA), but the transcriptional mechanisms governing its extreme accumulation are unclear. Although GDP-D-mannose-3',5'-epimerase (GME) is a key enzyme for AsA biosynthesis, its functional divergence and regulatory context in jujube are unknown. Here, we identified two GME paralogs, ZjGME1 and ZjGME2, in the jujube genome. Despite their common origin, expression profiling revealed that only ZjGME1 displayed a positive correlation with AsA content during fruit development, suggesting functional divergence. Transient overexpression of ZjGME1 confirmed its specific role in significantly enhancing AsA accumulation. Furthermore, to elucidate the upstream regulation, we identified a transcription factor, ZjNF-YC9, which directly binds to the ZjGME1 promoter and activates its expression to promote AsA accumulation. Our study thus uncovers a complete ZjNF-YC9-ZjGME1 transcriptional regulatory module, providing fundamental insights for the metabolic engineering of nutritional quality in fruits.
